Basrah Journal for Engineering Sciences

Artificial Neural Networks (ANN) have been applied to structural engineering in recent years. Most of the researches are based on backpropagation neural networks due to its well-studied theory. A backpropagation neural network has been used to predict the ultimate torsional strength of reinforced concrete rectangular beams. The effects of the parameters, such as the number of nodes in the input, output and hidden layers and the pre-process of the training patterns, on the behaviour of the neural network have been investigated. The algorithm called 'resilient propagation algorithm' has been used to the performance of the neural network. After training, the generalization of the neural network was tested by the patterns not included in the training patterns. Once the neural network has been trained, the ultimate torsional strength of reinforced concrete is obtained very easily and efficiently. Based on the ANN results, a parametric analysis was carried out to study the influence of parameters affecting the ultimate torsional strength of reinforced concrete beams and these results are compared with the equations of ACI-code.

Mathematical programming techniques have been used to minimize the cost of reinforced concrete counterfort retaining wall.The study presents a formulation based on elastic analysis and the ultimate strength method of design as per ACI-M318code. A computer program is generated to handle the considered problem. The formulation of optimization problem has been made by utilizing the interior penalty function method as an optimization method with the purpose of minimizing the objective function representing the cost of one-meter length of the counterfort retaining wall. This includes cost of concrete, reinforcement, and formwork. The design variables considered in this study are the dimensions and the amounts of reinforcement. It is found that the optimal spacing of counterforts equals about (0.214 to 0.366) of total height of wall. The optimum width of the base is found in the range (0.50 to 0.78) of the total height of the wall. Also the thickness of the stem is in the range(0.0284 to 0.0377) of the total height and it is less than half thickness of the base.

This research is devoted to investigate the effect of Carbon Fibre Reinforced Polymer (CFRP) strips on the behaviour and load carrying capacity of strengthened and repaired reinforced concrete corbels. Experimental investigation were carried. The experimental program variables include location, direction, amount of CFRP strips and effect of shear span to effective depth (a/d) ratio on the behaviour of strengthened corbels. All corbels had the same dimensions and flexural reinforcement and they were without horizontal shear steel reinforcement. The experimental results obtained from the adopted strengthening and repairing CFRP techniques showed a significant improvement in the behaviour and carrying capacity of the tested corbels. An increase of about (44.5 - 60) % in the ultimate load has been obtained for specimens strengthening by inclined technique compared to the ultimate load of control corbel and (14.7 - 31.2)% for specimens strengthening horizontal technique. For corbels repaired with CFRP strips, an increase of (56%) with respect to the ultimate load of control corbel is achieved. Also the strengthened corbels show stiffer load deflection response than corresponding control corbels (unstrengthened corbels).

The paper presents an experimental and theoretical study on the behavior of circular concrete filled aluminum tubular columns. The main purpose of the experimental program was to investigate the structural behavior of aluminum-concrete composite columns under axial compression loading conditions. Twenty four specimens were tested to investigate the effect of diameter, D/t ratio and slenderness ratio of a aluminum tube on the load carrying capacity of the concrete filled tubular columns. Diameter to wall thickness ratio ranged between 11.9 ≤ D/t ≤ 22.8, and the length to tube diameter ratios of 3 ≤ L/D ≤ 10 were investigated. The main purpose of the theoretical investigation was to predict the strength of aluminum -concrete composite columns subjected to axial compression loading conditions. The empirical equations proposed in the present study are capable of predicting the values of ultimate loads of aluminum -concrete composite columns and were in good agreement with the experimental values. The average values of ratios of experimental to predicted values of ultimate loads are 1.0104 for the proposed empirical equations. The circular hollow section tubes were fabricated by extrusion using 6061-T6 heat-treated aluminum alloy. The column strengths, load-axial shortening relationship and failure modes of columns were presented.

The analysis of raw domestic sewage has a greater importance for design of an effective and economic rational sewage treatment. The objectives of this study are to determine the chemical, physical and Biochemical characteristics of raw domestic sewage for Basrah city. Results show that; the strength of Basrah raw domestic sewage can be classified as a strong strength concentration wastewater due to high levels of organic loading rate BOD5, COD. Also, it can be seen a very high concentrations of TDS , CL- and increasing in EC levels above the typical limits due to the salinity of domestic water supply in Basrah. High concentrations of oil and grease were found as result of misuse of the sewerage system. While the values of pH, temperature, nutrients and the number of FC are within the typical acceptable limits.

A part of Basra water network which is near to Bradia water treatment plant is analyzed by using water cad program, water cad is also used for studying the water quality in the model by calculating the age and chlorine concentration for each pipe on the model. This model consist of (21)pipe ,(15)node or junction ,(6)loops, two water pumps one is operated and the second is stand by(each pump has a discharge equal to 0.6 mP 3 P/sec and a head of 60 m and an electrical control which related with the elevation of water in the tank),one elevated tank &one reservoir of water. The model studied hydraulically for two cases, the first case when the pump is power on and the second case when the pump is power off. Also the direction and discharge for each pipe are calculated. Different results are obtained in two cases. Also the results of water quality studies show that both the age of water and chlorine concentration at any pipe depended on its location with respect to the water treatment plant. Finally the calibration of the model is done in order to check the accuracy of the results.

In this study a two dimensional, steady state propagation of the laminar premixed flame was numerically and experimental are investigated. The energy, momentum, continuity equations for species and global reaction mechanism with equation of stat for ideal gases were solved. Constant temperature boundary condition is applied on axi – symmetric in y – direction domain.
The governing equations were discretized by using computation fluid dynamics (CFD) and finite-volume method - central differencing scheme, then solved using Gauss-Seidel Iteration method on uniformed grid with VISUAL BASIC code. Effects of equivalence ratio and initial temperature of fresh gases (air – fuel mixture) were investigated for three types of fuel Methane, Propane and Butane. Also the flame speed and flame temperature were experimentally measured for air – fuel (Methane, Propane, Butane and LPG) mixtures. The burning velocity was calculated depending on the flame speed and flame temperature measuring. The flame speed and flame temperature were measured by using optical technique. Effects of equivalence ratio and initial temperature of fresh gases (air – fuel mixtures) on flame speed and flame temperature are investigated experimentally. Results were generated for the detailed description of the local fluid flow and heat transfer characteristics including temperature, axial velocity, density and mole fractions profiles. For example the flame speed reached 274.4 cm/s as a maximum value at Ø=1.1 for propane air mixture, and flame temperature comparison give a good agreement between theoretical and experimental results at rich mixtyre

The performance of a five-holed conical probe ( which has a conical head with four holes symmetrically placed on the cone surface and one at the truncated tip) for the measurements of fluid velocity in three dimensional incompressible flow was investigated in air in an open circuit subsonic wind tunnel . The air velocity ranged from 15 – 45 m/s and the Reynolds number ranged from 40000 to 100000 based on the cone base diameter. The methods of calibration and use of the probe are given where the measurements of one angle and three pressures are sufficient to give the three components of velocity, static and total pressure. The conical head probe is easier to manufacture than the spherical head probe and has the advantage of having clear fluid separation points at the cone base whereas the fluid separation on the spherical probe is not well defined and depends on the Reynolds number.

In this research, the effect of seawater environments and surface roughness on uniform corrosion rate of carbon steel (A516 grade 65) was studied depending on the experimental work and artificial neural network modeling. The experimental work involves chemical composition, samples machining, roughness measurements (for carbon steel specimens), conductivity and salinity measurements (for seawater), and uniform corrosion test. Weight loss technique was employed in determining the uniform corrosion rate in carbon steel material. Also, artificial neural network (ANN) model was built to predict the values of uniform corrosion rate (mpy) at different values of conductivity, salinity for seawater and roughness factor for carbon steel depending on the experimental results which were used train and test the ANN. The results obtained of uniform corrosion rate by ANN predictions are shown to be agreed well against experimental values. i.e. correlation coefficient, R=0.9974

Dynamic behavior of pipe conveying fluid at different cross section is investigated. Three kinds of supports are used, which are flexible, simply and rigid supports. The type effect of support on vibration characteristics and dynamic specification are studied. Also, the effect of some design parameters such as pipe material and Reynold numbers are investigated. The governing equations of motion for this system are derived using the finite element method which depends on beam theory. A finite element software (ANSYA-11) is presented to find first three eigenvalue (natural frequency) and eigenvector (mode shape) for pipe system in modal analysis. Velocity and pressure distribution are evaluated in a single phase fluid flow. A coupled field fluid-structure analysis was then performed by transferring fluid forces, solid displacements, and velocity across the fluid-structure interface. Finally the effective stresses (Von mises stress) in piping system are predicted in static analysis at various Reynold numbers, pipe material and pipe supports.

This paper presents a diagnostic technique for power quality analysis against different disturbances in electrical power source. The presented technique utilizes a wavelet packet transform (WPT)-based a proposed algorithm for monitoring and detection various disturbances occurring in supply voltage signal and in supply frequency. The values and the time locations for low and high frequency coefficients are determined up to level six and compared with a threshold determined from the operation of healthy source. The proposed technique is tested on certain cases and the simulated results indicate that this technique is effective for detecting and monitoring different mentioned disturbances.